Separated prosthetic foot with transverse arch

ABSTRACT

A separated prosthetic foot with a transverse arch belongs to the technical field of manufacturing of artificial limbs. The characteristics of the transverse arch of the human foot are combined into the previous transverse-straight carbon fiber foot design to improve the stiffness of the prosthetic foot and reduce the weight of the prosthetic foot. A forefoot part employs a separated curved plate design, and two simple curved plates with different curvatures are used for simulating a complex curved surface of the transverse arch of the human, such that the manufacturing cost is reduced, and the various parts of the sole are non-uniform in stiffness distribution: the outer side of the foot is a single-layer forefoot plate with a smaller curvature and minor stiffness; and the inner side of the foot is a double-layer stacked forefoot plate, and the lower layer plate has a large radius in curvature and stiffness.

CROSS REFERENCE TO RELATED APPLICATION

This patent application claims the benefit and priority of Chinese Patent Application No. 202110667789.6, filed on Jun. 16, 2021, the disclosure of which is incorporated by reference herein in its entirety as part of the present application.

TECHNICAL FIELD

The present disclosure belongs to the technical field of the manufacturing of artificial limbs, and in particular relates to a prosthetic foot designed by combining the characteristics of a transverse arch of a human foot and the plantar pressure center change rule.

BACKGROUND ART

Amputation places a burden on individuals, families and societies, while fitting prosthesis to reconstruct a function of independent motion is an effective means to improve the self-care level and the ability of reengaging in social activities of the amputee. As the only part of the human body in contact with the ground for support, the foot is an important part of the lower limb. A prosthetic foot is a prosthetic component for compensating the function of an ankle system of the human body, the performance of which is directly related to the overall function of the prosthesis. The design of the prosthetic foot has always been based on the characteristics of the longitudinal arch of the human foot as a reference to achieve the purposes of increasing the overall elasticity of the prosthetic foot and reducing the impact during contact with the ground. Carbon fiber reinforced composites have been widely used in prosthetic feet with superior performance. The performance of the carbon fiber composites have a certain directionality, which leads to great strength of the carbon fiber prosthetic foot in a foot length direction, but poor strength in a foot width direction. Due to the transverse-straight carbon fiber prosthetic foot having a uniform thickness which is poor in dynamic response to different road surfaces and different motion states, more ground impact force is transferred to the stump during the period of bearing contact with the ground along with the support and propulsion period of the foot, and therefore, the stability and comfort of the prosthetic foot is limited. Research in recent years has show that the characteristics of the transverse arch of the human foot plays an important role in guaranteeing the overall stiffness of the foot, and the non-uniform curvature change of the transverse arch of the human foot plays an important role in guaranteeing the support and propulsion effects required by the movement of the human body and adapting to different road surfaces and different motion states. The stiffness of the lateral forefoot of the human foot is significantly smaller than that of the medial forefoot of the human foot. The plantar pressure center is transferred from the lateral forefoot to the medial forefoot during the stride of the human, which just corresponds to the curvature change rule of the transverse arch of the human foot. Therefore, it is necessary to provide a novel prosthetic foot with a transverse arch by further combining the curvature change characteristic of the transverse arch of the human foot on the basis of the characteristics of the longitudinal arch of the human foot, which can improve the overall stiffness of the prosthetic foot and reduce overall weight of the prosthetic foot; the dynamic response and use comfort under different road conditions and different motion states are improved, the machining and manufacturing are easier, the cost of the prosthetic foot is reduced, and thus the life quality and the exercise ability of the disabled can be better improved.

SUMMARY

For the shortcomings of an existing prosthetic foot made of composites, an objective of the present disclosure is to provide a prosthetic foot designed by combining the transverse arch characteristics of a human foot and the plantar pressure center change rule in a gait cycle. The transverse foot arch characteristics of the human foot are combined into the previous transverse straight carbon fiber foot design to improve the stiffness of the prosthetic foot and reduce the weight of the prosthetic foot. A forefoot part employs a separated curved plate design. Two simple curved plates having different curvatures are used for replacing a complex transverse arch curved surface of the human, thus reducing the manufacturing cost. Moreover, the sole of the prosthetic foot is designed with reference to the plantar pressure center change rule in a gait cycle and an action sequence of various parts of the human foot on the ground in the gait cycle, such that various parts of the sole are non-uniform in stiffness and can dynamically adapt to stiffness demands on different road surfaces and different gait stages. This will improve the overall performance of the prosthetic foot in terms of shock absorbing, body support and propulsion, stability, and user-comfort.

A separated prosthetic foot with a transverse arch comprises of a sole curved plate A, a heel curved plate B, a connecting piece C, a first screw and post set 1, a second screw and post set 2, a first rubber gasket 3, a first bolt 4, a second bolt 5, and a second rubber gasket 6. The connecting piece C, an upper carbon fiber curved plate 8 of the sole curved plate A, a lower carbon fiber curved plate 7 of the sole curved plate A, and the second rubber gasket 6 are sequentially arranged from bottom to top; the heel curved plate B, the lower carbon fiber curved plate 7 and the upper carbon fiber curved plate 8 of the sole curved plate A and the connecting piece are sequentially arranged from bottom to top, wherein the second rubber gasket 6 is located below the rear part of the lower carbon fiber curved plate 7; the second rubber gasket 6, the rear parts of the lower carbon fiber curved plate 7 and the upper carbon fiber curved plate 8 of the sole curved plate A and the bottom surface of a main body 10 b of the connecting piece C are fixedly connected by the first bolt 4 and the second bolt 5; the first rubber gasket 3 is located below the front part of the heel curved plate B; the first rubber gasket 3, the front part of the heel curved plate B, and the middle parts of the lower carbon fiber curved plate 7. The upper carbon fiber curved plate 8 of the sole curved plate A is fixedly connected by the first screw and post set 1 and the second screw and post set 2; the bottom surface of the main body 10 b in the connecting piece C is the same as the third arc curved surface of the rear arc part 8 a of the upper carbon fiber curved plate 8 in the sole curved plate A in size.

The sole curved plate A consists of the upper carbon fiber curved plate 8 and the lower carbon fiber curved plate 7; the upper carbon fiber curved plate 8 consists of a third rear arc part 8 a, a fourth rear arc part 8 b, a third middle transition part 8 c, a fourth middle transition part 8 d and a front flat-folded plate part 8 e; the third rear arc part 8 a, the fourth rear arc part 8 b, the third middle transition part 8 c, the fourth middle transition part 8 d and the front flat-folded pate part 8 e are smoothly connected into a whole in sequence from back to front; the third rear arc part 8 a is provided with a third rear hole 8 i and a fourth rear hole 8 h, the fourth rear arc part 8 b is provided with a third front hole 8 g and a fourth front hole 8 f; the third rear arc part 8 a and the fourth rear arc part 8 b are both arc curved surfaces having a uniform curvature, an arc radius of 65 to 70 mm, and a central angle of 70 to 80 degrees; the front flat-folded plate part 8 e is controlled by a fold line which is formed by connecting two straight lines having a height difference of 2 mm through arc smooth transition; the shapes of the third middle transition part 8 c and the fourth middle transition part 8 d change from arc transition to straight, and the curvature changes from a large radius of curvature to a small radius of curvature; the lower carbon fiber curved plate 7 consists of a first rear arc part 7 a, a second rear arc part 7 b, a first middle transition part 7 c, a second middle transition part 7 d and a front flat plate part 7 e; the first rear arc part 7 a, the second rear arc part 7 b, the first middle transition part 7 c, the second middle transition part 7 d and the front flat plate part 7 e are smoothly connected into a whole in sequence from back to front; the first rear arc part 7 a is provided with a first rear hole 7 i and a second rear hole 7 h, and second the rear arc part 7 b is provided with a first front hole 7 g and a second front hole 7 f, wherein the first rear arc part 7 a and the second rear arc part 7 b are arc curved surfaces having a uniform curvature which is greater than the curvature of the third rear arc part 8 a and the fourth rear arc part 8 b, a circular arc radius of 35 to 40 mm, and a central angle of 55 to 65 degrees; the front flat plate part 7 e is a flat plate, and the area of the front flat plate part is smaller than that of the front flat-folded plate part 8 e; the shapes of the first middle transition part 7 c and the second middle transition part 7 d changes from arc transition to straight, and the curvature changes from a large radius of curvature to a small radius of curvature; the upper carbon fiber curved plate 8 is located on the lower carbon fiber curved plate 7, the bottom surface of the upper carbon fiber curved plate 8 is in contact with the top surface of the lower carbon fiber curved plate 7, and the front flat plate part 7 e of the lower carbon fiber curved plate 7 is embedded in the front flat-folded plate part 8 e of the upper carbon fiber curved plate 8; the first rear hole 7 i, the second rear hole 7 h, the first front hole 7 g and the second front hole 7 f respectively correspond to the third rear hole 8 i, the fourth rear hole 8 h, the third front hole 8 g and the fourth front hole 8 f move up and down in sequence; the upper carbon fiber curved plate 8 and the lower carbon fiber curved plate 7 are integrally controlled by a sole longitudinal curve D in a front-back direction. The sole longitudinal curve D consists of a first sole longitudinal curve section 7 j and a second sole longitudinal curve section 7 k. The first sole longitudinal curve section 7 j is a straight line section with an inclination angle ranging from 18 degrees to 20 degrees; the second sole longitudinal curve section 7 k is a section of downward convex arc having an arc radius of 230 to 240 mm and a central angle of 20 to 22 degrees; the second sole longitudinal curve section 7 k is located at the front part of the sole longitudinal curve D, and the first sole longitudinal curve section 7 j. The second sole longitudinal curve section 7 k is in smooth and tangent connection.

The heel curved plate B consists of a top arc part 9 a, a first middle buffering transition part 9 b, a second middle buffering transition part 9 c and a bottom flat plate part 9 d; the top arc part 9 a, the first middle buffering transition part 9 b, the second middle buffering transition part 9 c and the bottom flat plate part 9 d are smoothly connected into a whole unit in sequence from front to back. The top arc part 9 a is a curved surface having a straight line in a front-back direction and an arc in a left-right direction, and having an arc radius of 30 to 35 mm and an central angle of 40 to 50 degrees, and the top arc part 9 a is provided with a first through hole 9 e and a second through hole 9 f; the bottom flat plate part 9 d is a straight plate having a width greater than that of the top arc part 9 a; the shapes of the first middle buffering transition part 9 b and the second middle buffering transition part 9 c change from arc smooth transition to straight, the curvature changes from a large radius of curvature to a small radius of curvature, such that the heel curved plate is fan-shaped; during the transition from the top arc part 9 a to the bottom flat plate part 9 d, the thickness of the heel curved plate changes from 4 mm to 2.5 mm; the heel curved plate B is integrally controlled by a heel longitudinal curve E in a front-back direction, and the heel longitudinal curve E consists of a first heel longitudinal curve section 9 g, a second heel longitudinal curve section 9 h and a third heel longitudinal curve section 9 i; the first heel longitudinal curve section 9 g is a downward convex arc having an arc radius of 70 to 75 mm and a central angle of 38 to 42 degrees; the second heel longitudinal curve section 9 h is an upward convex arc having an arc radius of 35 to 40 mm and a central angle of 55 to 60 degrees; the third heel longitudinal curve section 9 i is a straight line with an inclination angle of 18 to 20 degrees; the first heel longitudinal curve section 9 g, the second heel longitudinal curve section 9 h and the third heel longitudinal curve section 9 i are in smooth and tangent connection in sequence from back to front.

The connecting piece C consists of a square conical head 10 a and the main body 10 b, wherein the middle of the main body 10 b is provided with a cavity 10 e, the bottom end of the main body 10 b is provided with a first threaded hole 10 c and a second threaded hole 10 d; the square conical head 10 a is fixedly connected to the center of the upper end of the main body 10 b, the bottom surface of the main body 10 b is an arc curved surface having an arc radius of 65 to 70 mm and a central angle of 65 to 75 degrees.

Corresponding to a gait cycle of a normal person, the plantar pressure center gradually moves forwards from the heel to the lateral forefoot and then is gradually transferred from the lateral forefoot to the medial forefoot. The plantar pressure borne by the human foot in different ground-contacting stages is different, and the stiffness required by different parts of the human foot is also different. The process of the prosthetic foot making contact with the ground is one gait cycle. The gravity center of the body is located on the heel curved plate B and then is gradually transferred from the heel curved plate B to the outer side of the sole curved plate A, i.e., the outer side of the front flat-folded plate part 8 e of the upper carbon fiber curved plate 8 in the sole curved plate A. At this moment, only the front flat-folded plate part 8 e of the upper carbon fiber bent plate 8 is stressed. Due to small radius of curvature, minor stiffness and significant deformation amount after being stressed, the front flat-folded plate part 8 e of the upper carbon fiber bent plate 8 can better adapt to various road conditions can absorb the impact of the foot in the landing process in the normal motion process to play a role in buffering and energy storage, and can also adapt to bumpy road surfaces, thus making the prosthetic foot have better stability and comfort in the process of walking on different road surfaces. Afterwards, the gravity center of the body is transferred from the outer side of the sole curved plate A to the inner side, i.e., the front flat plate part 7 e of the lower carbon fiber curved plate 7, the inner side of the front flat-folded plate part 8 e of the upper carbon fiber curved plate 8 in the sole curved plate A, and at the moment, the lower carbon fiber curved plate 7 and the upper carbon fiber curved plate 8 in the sole curved plate A are stacked together to be stressed jointly. The thickness of the equivalent carbon fiber plate formed integrally is significant; and as the curvature of the lower carbon fiber curved plate 7 is larger than that of the upper carbon fiber curved plate 8. The equivalent stiffness is larger after the two curved plates are stacked and the supporting and propulsion effects in the gait cycle are better.

The present disclosure has the beneficial effects that:

1. The transverse arch of a human foot plays an important role in guaranteeing the stiffness of the human foot. In accordance with the present disclosure, the characteristics of the transverse arch of the human body are combined into the prosthetic foot containing only the characteristics of a longitudinal arch The transverse-straight carbon fiber plate is changed into the transverse-bent carbon fiber plate, such that the weight of the prosthetic foot is greatly reduced while the stiffness required by the use of the prosthetic foot is ensured. Meanwhile, the sole part employs a separated curved plate design. Two simple curved plates having different curvatures are used for replacing a complex transverse arch curved surface of the human body, thus reducing the manufacturing cost.

2. A double-layer separated prosthetic foot sole is designed with reference to the characteristics of a plantar pressure center line in the gait cycle and the action sequence of various parts of the foot on the ground in the gait cycle, such that the various parts of the sole are non-uniform in stiffness distribution. The outer side of the prosthetic foot is a single-layer forefoot plate with a smaller curvature and minor stiffness; the inner side of the prosthetic foot is a double-layer forefoot plate with a large radius of curvature and significant stiffness. Different curvatures and different thicknesses can dynamically meet the stiffness requirements of different road surfaces and different walking stages, further improving the motor performance in terms of shock absorbing, body support and propulsion, stability, and user-comfort.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an axonometric view (rear right direction) of a separated prosthetic foot with a transverse arch;

FIG. 2 is an axonometric view (front right direction) of a separated prosthetic foot with a transverse arch;

FIG. 3 is an axonometric view (right bottom direction) of a separated prosthetic foot with a transverse arch;

FIG. 4 is an exploded view (front right direction) of a separated prosthetic foot with a transverse arch;

FIG. 5 is an axonometric view (front right direction) of a segmented section of an upper carbon fiber curved plate 8;

FIG. 6 is an axonometric view (front right direction) of a segmented section of a lower carbon fiber curved plate 7;

FIG. 7 is an axonometric view (front right direction) of a segmented section of a heel curved plate B;

FIG. 8 is a right view of a sole longitudinal curve D and a heel longitudinal curve E;

FIG. 9 is an axonometric view (front right direction) of a connecting piece;

In the drawings: A—sole curved plate; B—heel curved plate; C—connecting piece; D—sole longitudinal curve; E—heel longitudinal curve; 1—first screw and post set; 2—second screw and post set; 3—first rubber gasket; 4—first bolt; 5—second bolt; 6—second rubber gasket; 7—lower carbon fiber curved plate; 7 a—first rear arc part; 7 b—second rear arc part; 7 c—first middle transition part; 7 d—second middle transition part; 7 e—front flat plate part; 7 f—second front hole; 7 g—first front hole; 7 h—second rear hole; 7 i—first rear hole; 7 j—first sole longitudinal curve section; 7 k—second sole longitudinal curve section; 8—upper carbon fiber curved plate; 8 a—third rear arc part; 8 b—fourth rear arc part; 8 c—third middle transition part; 8 d—fourth middle transition part; 8 e—front flat-folded plate part; 8 f—fourth front hole; 8 g—third front hole; 8 h—fourth rear hole; 8 i—third rear hole; 9 a—top arc part; 9 b—first middle buffering transition part; 9 c—second middle buffering transition part; 9 d—bottom flat plate part; 9 e—first through hole; 9 f—second through hole; 9 g—first heel longitudinal curve section; 9 h—second heel longitudinal curve section; 9 i—third heel longitudinal curve section; 10 a—square conical head; 10 b—main body; 10 c—first threaded hole; 10 d—second threaded hole; 10 e—cavity.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The following describes the present disclosure with reference to the accompanying drawings.

As shown in FIG. 1 to FIG. 4 , a separated prosthetic foot with a transverse arch comprises a sole curved plate A, a heel curved plate B, a connecting piece C, a first screw and post set 1, a second screw and post set 2, a first rubber gasket 3, a first bolt 4, a second bolt 5, and a second rubber gasket 6. The connecting piece C, an upper carbon fiber curved plate 8 of the sole curved plate A, a lower carbon fiber curved plate 7 of the sole curved plate A, and the second rubber gasket 6 are sequentially arranged from bottom to top; the heel curved plate B, the lower carbon fiber curved plate 7 and the upper carbon fiber curved plate 8 of the sole curved plate A and the connecting piece are sequentially arranged from bottom to top, wherein the second rubber gasket 6 is located below the rear part of the lower carbon fiber curved plate 7; the second rubber gasket 6, the rear parts of the lower carbon fiber curved plate 7 and the upper carbon fiber curved plate 8 of the sole curved plate A and the bottom surface of a main body 10 b of the connecting piece C are fixedly connected by the first bolt 4 and the second bolt 5; the first rubber gasket 3 is located below the front part of the heel curved plate B; the first rubber gasket 3, the front part of the heel curved plate B, and the middle parts of the lower carbon fiber curved plate 7 and the upper carbon fiber curved plate 8 of the sole curved plate A are fixedly connected by the second screw and post set 1 and the second screw and post set 2. The bottom surface of the main body 10 b in the connecting piece C is the same as the arc curved surface of the third rear arc part 8 a of the upper carbon fiber curved plate 8 in the sole curved plate A in size.

As shown in FIG. 5 , FIG. 6 and FIG. 8 , the sole curved plate A consists of the upper carbon fiber curved plate 8 and the lower carbon fiber curved plate 7; the upper carbon fiber curved plate 8 consists of a third rear arc part 8 a, a fourth rear arc part 8 b, a third middle transition part 8 c, a fourth middle transition part 8 d and a front flat-folded plate part 8 e; the third rear arc part 8 a, the fourth rear arc part 8 b, the third middle transition part 8 c, the fourth middle transition part 8 d and the front flat-folded plate part 8 e are smoothly connected into a whole unit in sequence from back to front; the third rear arc part 8 a is provided with a third rear hole 8 i and a fourth rear hole 8 h, the fourth rear arc part 8 b is provided with a third front hole 8 g and a fourth front hole 8 f The third rear arc part 8 a and the fourth rear arc part 8 b are both arc curved surfaces having a uniform curvature, an arc radius of 65 to 70 mm, and a central angle of 70 to 80 degrees; the front flat-folded plate part 8 e is controlled by a fold line which is formed by connecting two straight lines having a height difference of 2 mm through arc smooth transition; the shapes of the third middle transition part 8 c and the fourth middle transition part 8 d change from arc transition to straight, and the curvature changes from a large radius of curvature to a small radius of curvature; the lower carbon fiber curved plate 7 consists of a first rear arc part 7 a, a second rear arc part 7 b, a first middle transition part 7 c, a second middle transition part 7 d and a front flat plate part 7 e. The first rear arc part 7 a, the second rear arc part 7 b, the first middle transition part 7 c, the second middle transition part 7 d and the front flat plate part 7 e are smoothly connected into a whole unit in sequence from back to front; the first rear arc part 7 a is provided with a first rear hole 7 i and a second rear hole 7 h, and second the rear arc part 7 b is provided with a first front hole 7 g and a second front hole 7 f, wherein the first rear arc part 7 a and the second rear arc part 7 b are arc curved surfaces having a uniform curvature which is greater than the curvature of the third rear arc part 8 a and the fourth rear arc part 8 b, a circular arc radius of 35 to 40 mm, and a central angle of 55 to 65 degrees. The front flat plate part 7 e is a flat plate, and the area of the front flat plate part is smaller than that of the front flat-folded plate part 8 e; the shapes of the first middle transition part 7 c and the second middle transition part 7 d change from arc transition to straight, and the curvature changes from a large radius of curvature to a small radius of curvature; the upper carbon fiber curved plate 8 is located one the lower carbon fiber curved plate 7. The bottom surface of the upper carbon fiber curved plate 8 is in contact with the top surface of the lower carbon fiber curved plate 7, and the front flat plate part 7 e of the lower carbon fiber curved plate 7 is embedded in the front flat-folded plate part 8 e of the upper carbon fiber curved plate 8. The first rear hole 7 i, the second rear hole 7 h, the first front hole 7 g and the second front hole 7 f respectively correspond to the third rear hole 8 i, the fourth rear hole 8 h, the third front hole 8 g and the fourth front hole 8 f up and down in sequence. The upper carbon fiber curved plate 8 and the lower carbon fiber curved plate 7 are integrally controlled by a sole longitudinal curve D in a front-back direction. The sole longitudinal curve D consists of a first sole longitudinal curve section 7 j and a second sole longitudinal curve section 7 k, and the first sole longitudinal curve section 7 j is a straight-line section with an inclination angle ranging from 18 degrees to 20 degrees. The second sole longitudinal curve section 7 k is a section of downward convex arc having an arc radius of 230 to 240 mm and a central angle of 20 to 22 degrees; the second sole longitudinal curve section 7 k is located at the front part of the sole longitudinal curve D, and the first sole longitudinal curve section 7 j and the second sole longitudinal curve section 7 k are in smooth and tangent connection.

As shown in FIG. 7 and FIG. 8 , the heel curved plate B consists of a top arc part 9 a, a first middle buffering transition part 9 b, a second middle buffering transition part 9 c and a bottom flat plate part 9 d. The top arc part 9 a, the first middle buffering transition part 9 b, the second middle buffering transition part 9 c and the bottom flat plate part 9 d are smoothly connected into a whole piece in sequence from front to back. The top arc part 9 a is a curved surface having a straight line in a front-back direction and an arc in a left-right direction, and having an arc radius of 30 to 35 mm and a central angle of 40 to 50 degrees, and the top arc part 9 a is provided with a first through hole 9 e and a second through hole 9 f The bottom flat plate part 9 d is a straight plate having a width greater than that of the top arc part 9 a; the shapes of the first middle buffering transition part 9 b and the second middle buffering transition part 9 c change from arc smooth transition to straight, the curvature changes from a large radius of curvature to a small radius of curvature, such that the heel curved plate is fan-shaped. During the transition from the top arc part 9 a to the bottom flat plate part 9 d, the thickness of the heel curved plate changes from 4 mm to 2.5 mm. The heel curved plate B is integrally controlled by a heel longitudinal curve E in a front-back direction, and the heel longitudinal curve E consists of a first heel longitudinal curve section 9 g, a second heel longitudinal curve section 9 h and a third heel longitudinal curve section 9 i; the first heel longitudinal curve section 9 g is a downward convex arc having an arc radius of 70 to 75 mm and a central angle of 38 to 42 degrees. The second heel longitudinal curve section 9 h is an upward convex arc having an arc radius of 35 to 40 mm and a central angle of 55 to 60 degrees; the third heel longitudinal curve section 9 i is a straight line with an inclination angle of 18 to 20 degrees; the first heel longitudinal curve section 9 g, the second heel longitudinal curve section 9 h and the third heel longitudinal curve section 9 i are in smooth and tangent connection in sequence from back to front.

As shown in FIG. 9 , the connecting piece C consists of a square conical head 10 a and the main body 10 b, wherein the middle of the main body 10 b is provided with a cavity 10 e, the bottom end of the main body 10 b is provided with a first threaded hole 10 c and a second threaded hole 10 d; the square conical head 10 a is fixedly connected to the center of the upper end of the main body 10 b, the bottom surface of the main body 10 b is an arc curved surface having an arc radius of 65 to 70 mm and a central angle of 65 to 75 degrees. 

What is claimed is:
 1. A separated prosthetic foot with a transverse arch comprising: a sole curved plate, a heel curved plate, a connecting piece, a first screw and post set, a second screw and post set, a first rubber gasket, a first bolt, a second bolt and a second rubber gasket; wherein the sole curved plate consists of an upper carbon fiber curved plate and a lower carbon fiber curved plate; the upper carbon fiber curved plate consists of a third rear arc part, a fourth rear arc part, a third middle transition part, a middle fourth transition part and a front flat-folded plate part; the third rear arc part, the fourth rear arc part, the third middle transition part, the fourth middle transition part and the front flat-folded pate part are smoothly connected into a whole unit in sequence from back to front; the third rear arc part is provided with a third rear hole and a fourth rear hole, the fourth rear arc part is provided with a third front hole and a fourth front hole; the third rear arc part and the fourth rear arc part are both arc curved surfaces having a uniform curvature, an arc radius of 65 to 70 mm, and a central angle of 70 to 80 degrees; the front flat-folded plate part is controlled by a fold line which is formed by connecting two straight lines having a height difference of 2 mm through arc smooth transition, and the shapes of the third middle transition part and the fourth middle transition part change from arc transition to straight, and the curvature changes from a large radius of curvature to a small radius of curvature; the lower carbon fiber curved plate consists of a first rear arc part, a second rear arc part, a first middle transition part, a second middle transition part and a front flat plate part; the first rear arc part, the second rear arc part, the first middle transition part, the second middle transition part and the front flat plate part are smoothly connected into a whole unit in sequence from back to front; the first rear arc part is provided with a first rear hole and a second rear hole, and the second rear arc part is provided with a first front hole and a second front hole, wherein the first rear arc part and the second rear arc part are arc curved surfaces having a uniform curvature which is greater than the curvature of the third rear arc part and the fourth rear arc part, a circular arc radius of 35 to 40 mm, and a central angle of 55 to 65 degrees; the front flat plate part is a flat plate, and the area of the front flat plate part is smaller than that of the front flat-folded plate part; the shapes of the first middle transition part and the second middle transition part change from arch transition to straight, and the curvature changes from a large radius of curvature to a small radius of curvature; the upper carbon fiber curved plate is located one the lower carbon fiber curved plate, the bottom surface of the upper carbon fiber curved plate is in contact with the top surface of the lower carbon fiber curved plate, and the front flat plate part of the lower carbon fiber curved plate is embedded in the front flat-folded plate part of the upper carbon fiber curved plate; the first rear hole, the second rear hole, the first front hole and the second front hole respectively correspond to the second rear hole, the fourth rear hole, the third front hole and the fourth front hole up and down in sequence; the upper carbon fiber curved plate and the lower carbon fiber curved plate are integrally controlled by a sole longitudinal curve in a front-back direction, the sole longitudinal curve consists of a first sole longitudinal curve section and a second sole longitudinal curve section, and the first sole longitudinal curve section is a straight line section with an inclination angle ranging from 18 degrees to 20 degrees; the second sole longitudinal curve section is a section of downward convex arc having an arc radius of 230 to 240 mm and a central angle of 20 to 22 degrees; the second sole longitudinal curve section is located at the front part of the sole longitudinal curve, and the first sole longitudinal curve section and the second sole longitudinal curve section are in smooth and tangent connection; the heel curved plate consists of a top arc part, a first middle buffering transition part, a second middle buffering transition part and a bottom flat plate part; the top arc part, the first middle buffering transition part, the second middle buffering transition part and the bottom flat plate part are smoothly connected into a whole unit in sequence from front to back; the top arc part is a curved surface having a straight line in a front-back direction and an arc in a left-right direction, and having an arc radius of 30 to 35 mm and an central angle of 40 to 50 degrees, and the top arc part is provided with a first through hole and a second through hole; the bottom flat plate part is a straight plate having a width greater than that of the top arc part; the shapes of the first middle buffering transition part and the second middle buffering transition part change from arc smooth transition to straight, the curvature changes from a large radius of curvature to a small radius of curvature, such that the heel curved plate is fan-shaped; during the transition from the top arc part to the bottom flat plate part, the thickness of the heel curved plate changes from 4 mm to 2.5 mm; the heel curved plate is integrally controlled by a heel longitudinal curve in a front-back direction, and the heel longitudinal curve consists of a first heel longitudinal curve section, a second heel longitudinal curve section and a third heel longitudinal curve section; the first heel longitudinal curve section is a downward convex arc having an arc radius of 70 to 75 mm and a central angle of 38 to 42 degrees; the second heel longitudinal curve section is an upward convex arc having an arc radius of 35 to 40 mm and a central angle of 55 to 60 degrees; the third heel longitudinal curve section is a straight line with an inclination angle of 18 to 20 degrees; the first heel longitudinal curve section, the second heel longitudinal curve section and the third heel longitudinal curve section are in smooth and tangent connection in sequence from back to front; the connecting piece, the upper carbon fiber curved plate of the sole curved plate, the lower carbon fiber curved plate of the sole curved plate and the second rubber gasket are sequentially arranged from bottom to top; the heel curved plate, the lower carbon fiber curved plate and the upper carbon fiber curved plate of the sole curved plate and the connecting piece are sequentially arranged from bottom to top; wherein the second rubber gasket is positioned below the rear part of the lower carbon fiber curved plate, and second the rubber gasket, the rear parts of the lower carbon fiber curved plate and the upper carbon fiber curved plate in the sole curved plate and the bottom surface of a main body of the connecting piece are fixedly connected by a first bolt and a second bolt; the first rubber gasket is positioned below the front part of the heel curved plate; the first rubber gasket, the front part of the heel curved plate, and the middle parts of the lower carbon fiber curved plate and the upper carbon fiber curved plate in the sole curved plate are fixedly connected by the first screw and post set and the second screw and post set; the bottom surface of the main body in the connecting piece is the same as the arc curved surface of the third rear arc part of the upper carbon fiber curved plate in the sole curved plate in size.
 2. The separated prosthetic foot with the transverse arch according to claim 1, wherein the connecting piece consists of a square conical head and the main body; the middle of the main body is provided with a cavity, the bottom end of the main body is provided with a first threaded hole and a second threaded hole; the square conical head is fixedly connected to the center of the upper end of the main body, the bottom surface of the main body is an arc curved surface having an arc radius of 65 to 70 mm and a central angle of 65 to 75 degrees. 